First of all, you need to get a camera with a tripod and a remote control. You will require modern technology due to the fact that you will be starring, as well as directing this film.
A tripod can be lowered and raised to just about any height, and can be pointed in any direction. This will be your cameraman. You can shoot from many different angles and edit them together to create the impression of movement. To save time running back and forth, and to ensure that your continuity isn’t ruined, you’ll need a remote control. With this, you can start and stop the recording, and change from a wide shot to close-up.
Pick savvy locations. The trick to shooting with only one person is to find a place where you will not be interrupted. It’s going to be hard enough to make a movie by yourself, without having to deal with constant problems from other people. So plan for locations you know you can keep isolated, like your home or your car or even places in the middle of nowhere.
Explain the premise as everyone is going to notice that there is only one person in the movie, so you will need a good explanation. Either come up with a reason a single person would be isolated (trapped somewhere alone, the world has ended and they’re the only one left alive), or come up with a concept in which you can play more than one character (twins, story takes place in someone’s head). Once you’ve figured out which of these gimmicks works best for you, begin to build your story around that.
Set up shots that don't require much movement. The camera will be still and you don't want to move out of its range. Go for savvy wide shots mixed with close-ups.
Focus on the narrative. If the audience has to watch a single person in a film without much movement, the story must continually move forward with interesting plot points. Build dramatic tension throughout your script until you reach a peak at the end. If your story is a comedy, make the jokes short and punchy.